Nehemiah 13:29

29. Remember them All who were involved in the sin of Joiada’s son.

They… defiled the priesthood By being parties in the contraction of this marriage with a foreign woman. If it were sinful a breach of the law for any Israelite to marry a heathen wife, much more so for a son of the high priest to do it. The law expressly forbade a high priest to marry a widow, or a divorced woman, or profane, or harlot, or any but a virgin of his own nation. Leviticus 21:14. Hence this marriage of the high priest’s son was a breach of the covenant of the priesthood, and of the Levites. Compare Malachi 2:1-8. For though this apostate son of Joiada were not himself high priest, his marriage with a foreign woman was a stigma on his father’s family.